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KEITHLEY CONFIDENTIAL - PROPRIETARY
Differences between the new 6517B and
the 6517A version
The following document lists the known differences between the revised Model 6517B
and the previous 6517A. Although the goal was to make the 6517B as functionally
identical to the 6517A, there are some enhancements and changes that are documented so
that you can communicate specific changes to your customers.
Contents
1. Enhancements over 6517A
2. Hardware differences
3. Functional differences
3.1 Calibration
3.2 Communication
3.3 Measurements
3.4 New features
4. Specification changes from 6517A
1. Enhancements over 6517A
6517B now includes a 50,000 point battery-backed reading buffer, no longer limited
by the number of reading elements stored. 6517A capacity was 15,706 readings and
was limited by the number of elements stored in the buffer.
Faster reading rates to the internal buffer (~425rdgs/sec) and to the IEEE bus
(400rdgs/sec).
Up to 5x faster settling time when measuring low currents.
6517B now uses flash upgradeable firmware.
6517B now supports up to 115200 baud. The 6517A only supported up to 19200
baud.
User selectable line power values of 100, 120, 220, 240VAC instead of the 6517A
switch that selected either a range of 90-125VAC or 180-250VAC.
2. Hardware differences
Preamp, analog output, and common jacks are no longer 5-way binding posts. These
binding posts for the Electrometer Outputs have been replaced with safety jacks that
meet current safety standards. The ground lug has also been replaced with a pluggable
ground lead.
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The hardware interlock connector has been changed. The 6517B interlock connector
has been changed to a 4-pin Phoenix Connector compared to the 4-pin DIN connector
on the 6517A. The old connector has been obsoleted. To accommodate the new
connector, two new accessories have been added:
6517B-ILC-3: 4-pin Phoenix connector to 4-pin DIN Interlock Cable has been
added to support use with the 8009A Resistivity Test Chamber.
CS-1305: Interlock Connector
The interlock is now a real hardware interlock for the operation of the High
Voltage power supply. This is to bring the unit up to the latest safety
standards. Note that because of this, the 6517B voltage source will not operate
without the interlock whereas the 6517A voltage source would operate
without an interlock connection.
The Digital I/O connector has been changed to a DB9 male connection instead of the
older mini DIN connector.
External trigger signals are part of the digital I/O connector. Space limitations
prohibited the BNC connectors. BNC connectors were redundant and market
demands no longer required them.
The main input jack on the rear panel was moved away from the rear panel plastic
foot to improve customer accessibility and ease of use.
The voltage source operate indicator is smaller (same design as 6221). For
consistency with newer models, the 6517B indicator has been changed to Blue in
color (No longer Red) and centered in the right side front panel.
The line voltage selector is now hidden under the left front "foot bracket" that holds
the handle onto the box. There was no room on the rear panel to place the switch. The
switch allows the selection of 4 different input voltages: 100V / 120V / 220V / 240V,
not just 2 as in the 6517A version. The line fuse remains changeable from the rear
panel if the instrument.
3. Functional differences
3.1 Calibration
Front panel calibration is no longer supported with the 6517B due to the complexities
of the new calibration requirements. A customer front panel calibration would have
been very tedious, time consuming, and would have been very easy to make mistakes
due to the number of measurements that would have to be entered manually. The
customer can still calibrate the unit over the GPIB bus. The 6517B calibration
commands are provided in the service manual. Since the front panel calibration is no
longer supported, the front panel calibration switch is no longer present. Calibration is
now unlocked with a password.
Voltage and current offset calibration is no longer needed outside of normal
calibration. The 6517A required this, but was not implemented correctly. The 6517B
has an improved voltage and current offset calibration, but requires additional
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KEITHLEY CONFIDENTIAL - PROPRIETARY
equipment. Because of this requirement, the voltage and current offset calibration was
removed from the front panel menus as it is no longer necessary for the user to
perform this periodically.
3.2 Communication
The original 617 DDC emulation language is no longer supported.
GPIB talk-only mode is no longer supported. This was a little-used feature from the
6517A.
RS-232 parity, data, and stop bit settings are now fixed at N,8,1. There is little need to
use anything besides this setting, and the 6517B hardware would have difficulty
supporting all the possible settings the 6517A had.
3.3 Measurements
The "Out-Of-Limit" message now applies whenever the input signal exceeds the
maximum input range of the A/D, which is approximately 120% of range. The 6517A
could show "Underflow" when measuring resistance in this condition, which is
confusing. The 6517B manuals have been updated accordingly to include a better
description of the Overflow/Out-Of-Limit indications.
Readings can be displayed when ZeroCheck is turned on. This user selectable setting
for this functionality is accessed by pressing CONFIG and Z-CHK.
The Zero Check function (when turned on) now presents a 1 MegOhm load to the
input terminal (referenced to input low). This was necessary for updated ESD and
stability requirements.
3.4 New features
All non-volatile memory can be reset to defaults by the user for data security.
Specification changes from 6517A
Section Spec Description 6517A Spec New 6517B Spec
NMRR: 60dB on 2V, NMRR: 2V and 20V
Legacy spec problem. 20V, >55dB on 200V, at range > 60dB, 200V
Need to add line sync 50Hz or 60Hz